Tone generator



FIG. 1 is a front elevation of a tone generator showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a rear elevation thereof;

FIG. 5 is a left side elevation thereof; and,

FIG. 6 is a right side elevation thereof. 

The ornamental design for a tone generator, as shown and described. 